Urinary incontinence is a condition characterized by involuntary loss of urine beyond the individual's control. One cause for this loss of control is damage to the urethral sphincter caused by, for example, prostatectomy, radiation therapy or pelvic accidents. Other causes of incontinence include bladder instability, over-flowing incontinence and fistulas.
Currently, there are a few known surgical treatments for male incontinence, including the implantation of an Artificial Urinary Sphincter (e.g. AMS Sphincter 800 available from American Medical Systems, Minnetonka, Minn.), the implantation of a bone-screw fixated male sling (e.g. AMS InVance, available from American Medical Systems), and a few other procedures. Other procedures that have been largely discontinued include the implantation of a kaufman III Prosthesis beneath the urethra. All of these prostheses exert a force on the urethra to prevent unintentional voiding of the bladder.
An improved urethral prosthesis has also been reported, in which a fluid filled chamber is incorporated into the prosthesis to provide improved treatment of incontinence. For example, U.S. Pat. No. 6,502,578 and U.S. Publish Patent Application 2001/0023356, both to Raz et al. report an apparatus and method for treatment of male incontinence in which a “hammock-like” prosthesis is positioned between the descending rami of the pubic bone. The prosthesis includes an inflatable balloon device positioned to provide passive compression on the bulbar urethra to prevent voiding of the bladder. The volume of the balloon may be adjusted after implantation in a patient with a needle and syringe device.
PCT Published Application No. WO 00/74633 A2 reports a urethral prosthesis including a tape having an expandable pillow adapted to be positioned between the tape and the urethra after implantation. The pillow may be expanded by injecting bulking agent into the pillow, resulting in a vertical lifting against the urethra.
U.S. Pat. No. 3,789,828 to Schulte reports a urethral prosthesis including a capsule having a liquid filled cavity and two flexible prosthesis ties. U.S. Pat. No. 4,019,499 to Fitzgerald reports a compression implant for urinary incontinence including a cap with an external planar pressure face, a base with an external bearing face and a wall connecting the cap and the base. The cap, base and wall form a cavity that may be filled with an adjustable amount of fluid to adjust the force exerted against the urethra after implantation.
U.S. Pat. No. 6,117,067 to Gil-Vernet reports a device for adjusting the height of internal anatomical organs. The device includes a chamber with a volume that may be adjusted by varying the amount of fluid in the chamber. A capsule connected to the chamber via a tube may be used to increase or decrease the amount of fluid in the chamber. Each end of a thread is connected to an end of the chamber, and the thread is adapted to surround an organ. By adjusting the volume of the chamber the thread lifts or lowers the organ as desired.
PCT Application 00/18319 reports a prosthesis including a flexible elongate member, a distensible portion, a conduit and a valve. The distensible portion is bonded to the elongate member and may be filled with a fluid. The conduit provides fluid communication between the distensible portion and the valve. Fluid may be injected into the valve to adjust the pressure of the distensible portion.
Although urethral prostheses that incorporate adjustable fluid-filled chambers may reduce unintentional voiding of the bladder, current chambers may suffer from one or more drawbacks. For example, if the chambers are not sufficiently inflated before implantation, a clinician must inject additional fluid into the chamber to place sufficient force against the patient's urethra. However, this fluid puts additional strain on the prosthesis material, which is generally anchored to an anatomical structure in the body. Such strain may cause patient discomfort, or may even cause the prosthesis to fail. In another example, if the chamber exerts too much pressure on a patient's urethra, then the patient may be unable to void the bladder. This too would require a clinician to perform an additional procedure to adjust the fluid level in the chamber, which would subject the patient to additional risk of infection and may make the procedure more costly. Further yet, such devices have little tolerance for improvement or deterioration in the patient's incontinence condition. Thus, it would be advantageous to provide a male urethral prosthesis that overcomes one or more of these drawbacks.